1. Field of the Invention
The present invention generally relates to a mobile communication system. More particularly, the present invention relates to an antenna device for a Base Station (BS) in a mobile communication system.
2. Description of the Related Art
In a mobile communication system, a BS (including a Relay Station (RS)) typically collects data from Mobile Stations (MSs) via their connections and transmits the collected data to a switching network. The BS amplifies a transmission signal through a high-power amplifier within a BS body, transmits the amplified signal to an antenna device, and radiates it through the antenna device. The antenna device receives a signal from an MS and transmits the received signal to the BS body, for processing. For the purpose of providing a service, the antenna device is installed at a high place such as a building rooftop or a tower and the base station is installed on the ground within a building or under a tower.
As stated above, the antenna device is installed in an elevated position to maximize the propagation distance of a radio signal. In an urban area, typically, a post is put up on the rooftop of a building, a fixture is mounted onto the post, and a communication antenna is installed to the fixture.
Although the antenna device for the mobile communication system should be installed at an appropriate position to enable reliable wireless communications, such a site is hard to secure because the antenna device is considered as an obstacle to a living environment and thus building owners typically do not want antenna equipment installed. Therefore, it is difficult to find an installation site for the antenna device.
Especially in an urban area where people make mobile calls frequently, high cost is another obstacle to the siting of the antenna device.
In the meantime, street lamps for illuminating roads and surveillance cameras for night watch are installed to their separate posts downtown. Antenna devices, street lamps, surveillance cameras, etc. are installed on separate posts although they commonly require a post for installation, power supply, and a communication function. Accordingly, there are too many unnecessary and disfiguring posts in downtown or urban environments.